Sima Xin

Sima Xin (died 204 BC) was King of Sai in 206 BC during the Eighteen Kingdoms era. He sided with Xiang Yu during the Chu-Han Contention, and he committed suicide after being defeated at Chenggao.

Biography
Sima Xin served as a general and magistrate of the Qin dynasty, and, in 211 BC, he spared Xiang Liang, Xiang Bo, and Xiang Yu after they murdered a dissenting member of their group of Chu revolutionaries, as he was impressed with their loyalty to Chu and respected them. In 209 BC, he was sent to serve as Zhang Han's deputy during the Qin government's quelling of several rebellions against Qin Er Shi, and he and Zhang Han later joined Xiang Yu after the eunuch Zhao Gao refused to help them against the kingdom of Zhao and sent assassins to murder them. Xiang Yu made Sima Xin King of Sai, and Sima Xin later submitted to the Han king Liu Bang. In 205 BC, after Liu Bang was defeated by Xiang Yu at Pengcheng during the Chu-Han Contention, Sima Xin defected to Xiang Yu's side. His army was ambushed and defeated at Chenggao, forcing him to commit suicide.